It is often desirable for an equipment operator to know the rate and quantity of articles being dispensed by certain dispensing equipment. For example, farmers who use mechanized equipment to plant agricultural products must know the quantity of seeds that are being dispensed by the mechanized planting equipment in order to optimize crop production and yield in a given area. Often, a farmer must know the quantity of seeds being planted in each row by the mechanized planter in order to optimize production.
To provide rate and quantity information to farmers and other operators of equipment, a variety of sensors and systems have been developed which are capable of detecting that an article has passed along or through a predetermined path and displaying a total count representative of the total number of articles that are detected. In the case of mechanized seed planting equipment, most of the detecting sensors utilize electro-optical transducers which receive a light beam transmitted across a seed tube which light beam is interrupted or interfered with by the passage of seeds through the tube. Every time the light beam is interrupted or sufficiently diminished below some predetermined threshold, a "seed event" is said to occur and, for each seed event, the sensors typically send a signal to a central monitor which adds a count to the total count and displays the total count and other information.
These systems often miscount the number of seeds passing along the seed paths. For example, dirt or dust in and around the seed path can interrupt or reduce the light signal beneath the threshold of the optical sensor and thereby trigger a seed count which is higher than the actual number of seeds which passed through the seed path. Another error occurs when two or more seeds are lumped closely together as they travel through the seed tube. Because these closely lumped seeds interrupt the light beam only once, the sensor only "detects" a single seed and will count a lower number of seeds than the actual number which passed through the seed path. Yet another error occurs when one or more of the light beam emitters malfunctions and the counting system has no way of detecting that the emitters are not working properly.
Certain prior systems have employed electronic noise compensating circuitry in order to reduce the erroneous counts associated with dirt or other non-articles. Other systems have focused on the rate of change of the signal from the optical sensor in order to better detect closely overlapping articles or seeds. Still other systems have addressed the problem of discriminating between closely overlapping seeds by providing an optical sensing device with complicated mirrors and lenses which serve to create and maintain a more uniform light field.
Nonetheless, with the need to accommodate ever increasing dispensing rates, driven by the need to increase productivity, there is a need for a system that provides even greater accuracy at higher dispensing rates, where the probability of overlapping articles is great, coupled with the need for such a system that simplifies installation, set-up and maintenance and provides the operator with more detailed information relating to the performance of the seed planter or other article dispensing devices.